Background: A healthy mental adjustment to life is associated with a higher life expectancy than emotional disorders and stress. Age-related depression and dementia are major global public health issues that contribute to significant morbidity and disability among the elderly. Aims and Objectives: The aim of this study was to estimate the prevalence of depression and dementia among the elderly population residing in the rural field practice area of Medical College, Kolkata. Materials and Methods: This cross-sectional study was conducted among 110 elderly populations obtained through multistage random sampling, in the villages under ROHANDA health and wellness center using pre-tested, validated questionnaires called the short version of Geriatric depression scale -15, and Ascertain Dementia 8 to screen and estimate the prevalence of depression and dementia among the elderly. Results: The prevalence of depression and dementia among the elderly (mean age ± SD = 62.5 ± 6.69 years) was 18.2% and 17.3%, respectively. Increasing age, low socioeconomic status, low education, and nucleation of families were found to have significance in developing both dementia and depressive symptoms among the elderly. Binary logistic regression analysis was performed with the risk factors that found to be significantly associated with the development of depression and dementia. For depression type of family (adjusted odds ratio [AOR] 0.11; 95% confidence interval [CI] [0.013–0.983]), body mass index (AOR 7.07; 95% CI [2.104–23.755]) were found to be independent risk factors and for dementia age (AOR 13.60; 95% CI [3.168–58.375]), socioeconomic status (AOR 0.063; 95% CI [0.007–0.563]), marital status (AOR 7.83; 95% CI [1.767–34.696]) were found to be significant after controlling other relevant factors. Conclusion: As aging-related changes take place, depression and cognitive impairment in the elderly go undiagnosed. Therefore, early screening in primary care can aid in early diagnosis and the implementation of suitable interventions to lessen the severity and burden of the condition and enhance the quality of life.